Method and device for producing a cigarette filter unit

ABSTRACT

The invention relates to a method and a device for producing a cigarette filter unit wherein an external cover strip eventually shaped as a tube, is glued around the entire periphery of filter elements which are spaced and aligned axially within said tube, fluent filter material being disposed between adjacent pairs of filter elements within the tube.

United States Patent [1 1 Burrus et al.

[ METHOD AND DEVICE FOR PRODUCING A CIGARETTE FILTER UNIT [75]Inventors: Charles Burrus, Boncourt; Serge Boegli, Zurich, both ofSwitzerland [73] Assignee: F. J. Burrus & Cie, Boncourt, Switzerland 22Filed: July 14, 1972 21 Appl. No.: 271,639

[30] Foreign Application Priority Data July 16, 1971 Switzerland010464/71 [52] US. Cl. 93/1 C, 93/77 FT, 93/DIG. l [51] Int. Cl. A24c5/50 [58] Field of Search 93/77 FT, 1 C, DIG. 1

g [56] References Cited UNITED STATES PATENTS 12/1967 I Hall 93/77 FT [41 May 28, 1974 9/1968 Sexstone et al. 93/77 FT 12/1969 Sexstone 93/1 CPrimary ExaminerRoy Lake Assistant Examiner-James F. Coan Attorney,Agent, or FirmPierce, Scheffler & Parker [57] ABSTRACT The inventionrelates to a method and a device for producing a cigarette filter unitwherein an external cover strip eventually shaped as a tube, is gluedaround the entire periphery of filter elements which are spaced andaligned axially within said tube, fluent filter material being disposedbetween adjacent pairs of filter elements within the tube.

4 Claims, 8 Drawing Figures PATENTEUIAY 2 1914 SHEET 3 0F 4 Ital/H pm 2f:

PATENTEnm 28 m4 3 Q 8 1 2' 76 8 sum u or 4 Fig. 7

Fig.6

METHOD AND DEVICE FOR PRODUCING A CIGARETTE FILTER UNIT The presentinvention relates to a method and a device for producing a cigarettefilter unit having sections of fibrous and fluent filter materialarranged alternately within an external tube.

Known methods for producing a cigarette filter unit within whichsections of fibrous and fluent filter material are arranged one behindthe other generally involve the adhesion of the cover strip surroundingthe filter material along its overlapping edge zones. The disadvantageof this is in many cases that fluent filter mate rial penetrates betweenthe outside of the elements comprising fibrous filter material and thecover strip and enters the mouth of the smoker, which is veryunpleasant.

The object of the present invention is to create a method which does nothave this drawback.

The method in accordance with the invention is characterized in that aseries of filter elements uniformly spaced apart from each other andaligned axially in respect of each other are continuously attached on acontinuously supplied mouthpiece cover strip which is coated on the sidewhich comes into contact with the filter elements by a thermoplasticsplastics material, by

, means of at least localized softening of the thermoplastics plasticscoating by means of a first heating device, after which the filterelements and the cover strip are moved, with a view to the formation ofchambers which are located between the filter elements and provided witha supply aperture, past a filling member which is provided with at leastone filling aperture, a specific quantity of fluent filter materialbeing poured out of the filling member into the chambers located betweenthe filter elements, the edges of the cover strip then being made tooverlap with the result that the cover strip forms a closed tube,completely enclosing the filterelements and the fluent filter material,after which the cover strip is connected over the whole periphery of thefilter elements with the latter by means of softening the thermoplasticsplastics coating by means of a second heating device.

The present invention further provides a device for carrying out themethod in accordance with the invention which is characterized in thatit has a guide device which shapes the cover strip to form a tube whichcompletely encloses the filter elements and the chambers located betweenthem which are filled with fluent filter material in such a way that theedges of the cover strip overlap one another, and a sealing deviceprovided with an element which is adapted to be heated and to be placedon the tube which is to be sealed with a view to connecting to eachother the edges of the cover strip which overlap one another, by thefact that the heatable element is provided with a guide channel which isat least approximately semicircular in shape seen in cross-section, andwhose radius of curvature corresponds to the external radius of the tubeto be produced, in the fact that there is provided directly behind theguide channel of the heatable element a further analogous guide channelof a cooling member adapted to be placed on the tube with a view tosetting the heatsoftened adhesive and a further heatable elementlocated, seen along the direction of movement of the tube which is to besealed, behind the heatable element of the sealing device, a guidechannel of which connects the as yet unglued part of the cover stripwhich has been shaped'to form a tube to the filter elements. This devicehas the further advantage that as a result of the initial welding ofthat part of the cover strip containing the overlapping edges of thecover strip and the immediate cooling of the same a precise tubediameter is achieved without releasing the welded tube.

In order to avoid damage to the cover strip when the device isstationary it is expedient if the means for attaching the individualfilter elements on the cover strip comprise a heating element which isadapted to move towards and away from the side of the cover strip remotefrom the filter elements, and that an adjusting mechanism is provided tobring the heating element so close to the cover strip when the latter ismoved forwards that an adhesive which is located on the cover strip andsoftens under the influence of heat is softened at least locally, andwhen the cover strip is stationary moves it so far from the latter thatthe cover strip is not damaged by the heat radiating from the heatingelement.

The invention is explained below by way of example with the help of thedrawing. These show:

FIG. 1 a diagrammatic side view of a device for producing a cigarettefilter unit;

FIG. 2 a section along the line Il-Il in FIG. 3. through the fillingpart;

FIG. 3 a section along the line IIIIII in FIG. 2;

FIG. 4 a section on an enlarged scale along line IV-lV in FIG. 2;

FIG. 5 a section along line V-V in FIG. 1 to show the attachment part;

FIG. 6 a section along line VI-VI in FIG. 1 to show the upper weldingpart;

FIG. 7 a section along line VII-VII in FIG. I to show the cooling part;and

FIG. 8 a section along line VIII-VIII in FIG. 1 to show the lowerwelding part.

In the device shown in FIG. 1 the supply means for the continuous supplyof a series of cylindrical filter elements l and 2 made of fibrousmaterial, separated at uniform distances from each other and alignedaxially in respect of each other on to a continuously suppliedmouthpiece cover strip 3 have for example a machine 4, which is referredto in the cigarette industry as D.A .P.T.C.-machine made by Molins andis described in more detail in US. Pat. specification No. 2,957,285.This machine 4 is provided with two storage containers 5 for storingcylindrical filter material pieces made for example from cellulose andacetate and two rotatable cylinders 6 to receive the latter. The machine4 is driven via the chain drive 7.

Cylinders 6 are provided along their periphery with grooves runningparallel to their axes of rotation to receive the pieces of filtermaterial and have a specific number of radially running grooves intowhich rotatable knives engage with a view to subdividing the rodshapedpieces of filter material into the smaller filter elements' l and 2.

After the subdivision of the rod-shaped filter material pieces into thesmaller filter elements 1 and 2 the cylinders 6 pass the latter to atransport and distancing device 8, which moves the filter elements 1 and2 forwards in the direction of the arrow 9 alternating with each otherand axially aligned and simultaneously creates equal distances betweenthem.

T he filter elements 1 and 2 which are at a uniform of each other arecontinuously supplied to a mouth- 1, piece cover strip 3 which iscontinuously supplied in like manner, placed on the latter and, as canbe seen from FIG. 5, guided in a lateral direction through the guideparts and 1 1 and kept, by means of a clamping strip 12 which isarranged above the mouthpiece cover srip 3 and rotates synchronousthereto in their positions relative to each other.

The mouthpiece cover strip 3 is coated on the side facing the filterelements 1 and 2 with an adhesive which can be softened by heat, such asfor example a thermoplastics plastics material, so that it is possibleto attach the individual filter elemtns 1 and 2, immediately after theyhave been transferred on to the cover strip 3, to the latter with thehelp of a heating element 13 and thus to render impossible relativedisplacements towards each other, in other words a change in thedistance between them. The mouthpiece cover strip 3, as can be seen fromFIG. 5, rests on a support member 14, and the heating element 13 isadapted to be pressed from below through a slotted aperture in thesupport member 14 against the cover strip 3 and therefore indirectly.against the filter elements 1 and 2 which are to be attached. Thetemperature of the heating element 13 is preferably thermostaticallycontrolled. The arrangement of the heating element 13 is such that whenthe cover strip 3 is stationary, it is lifted off from the latter inorder to prevent the latter burning. This can be effected by anysuitable means such as by arranging the heating element 13 for pivotalmovement about an axle '50, an electromagnet 51 being used to raise theheating element into contact with the underside of the cover strip 3against a counterforce exerted by compression spring 52 which serves towithdraw the heating element away from the cover strip 3 when theelectromagnet 51 is deenergized. An adjustable stop 53 can be providedto. determine the distance that the heating element 13 is raised.

After the individual filter elements 1 and 2 have been attached on thecover strip 3 the latter is led on to an endless conveyor belt 15 andthese parts then arrive together in a guide rail which acts as a shapingmember, where the cover strip 3 is placed around the filter elements 1and 2 which are attached to it in at least approximately U-shape duringits forward movement.

7 This structure is then guided by means of the conveyor belt 15 to afilling part 16 which is shown in more detail in FIGS. 2, 3 and 4, saidmember serving to introduce fluent filter material, such as e.g.activated carbons, into the chambers 17 formed between the individualfilter elements 1 and 2. In order that the chamstorage container 18 ofthe filling member 16 is connected on its downward-directed outlet sidevia a slidingmember 19 which rests on the filter elements land 2 andencloses them by at least 180 to a suction device 21 which, seen alongthe direction of movement of the cover strip 3, is housed in front ofthe filling aperture of thefilling member 16. The width of the slidingmember 19 corresponds approximately to the diameter of the filterelements 1 and 2 which are to be encased in the cover strip 3, sidesurfaces 19a and 1% (FIG. 4) of the slidingmember 19 running parallel toeach other and to the direction of movement of the conveyor belt 15 andserve to provide a sealing structure of the surfaces 3a and 3b, whichface in opposite directions, of the arms of the cover strip 3 which isin the shape of a U. In this way the limited chambers 17 are formed bythe front edges of the filter elements 1 and 2, the cover strip 3 andthe sliding surface of sliding member 19.

The distance between the suction aperture 22 located in the slidingsurface and the filling aperture 20 is greater than the length a of thechambers 17 formed between the filter elements 1 and 2, with the resultthat during the forward movement of the latter these are completelyenclosed in a practically air-tight manner between the suction aperture22 and the filling aperture 20 as far as the filter elements 1 and 2,with the result that the suction arrangement 21 can evacuate thesechambers through filter elements 1 and 2. The arms of the U-shaped coverstrip 3 are as a result of the underpressure prevailing in the chambers17 pressed in practically air-tight manner against the side surfaces 19aand 19b of slide member 19.

The chambers which have been evacuated in this way then pass under theexit slot 20 of the storage container 18 which forms the fillingaperture, whereupon the fluent filter material located in th latter isdrawn in bursts into the chambers 17 emerging under the sliding surface.

In order to help the chambers 17 to be completely filled and the fluentfilter material in the storage container l8 and in the outlet slot 20 toslide downwards, the filling member 16 is provided with a vibrator 23,the effect of this being that the filling part 16 which is suspended inresilient manner on leaf springs 24 (FIG. 3) oscillates at Hz in avertical plane.

A semicircular-shaped stipping edge 30 is provided at the end of theoutlet slot 20 and this limits the crosssection of the filter elements 1and 2 passing through and strips off surplus fluent filter material. Asthis stripping edge 30 is subjected to considerable wear while thedevice is in operation it is located in an exchangeable strippingsection 31 which is'adapted to be inserted into the slide member 19.

The stripping member 31 is additionally provided on its underside withtransverse grooves 31a which strip any grains of the fluent filtermaterial which may still be found on the filter elements away from thelatter, pick them up and pass them into the following chambers l7.

In order to modify the size of the outlet slot 20 to suit the size ofgrain of the fluent filter material, the lower part 32 of the storagecontainer 18 is designed in the shape of a cylinder in which ascoop/trough-shaped closure member 33 is housed, this being adjacent tothe inside of this cylinder-shaped part 32 and adapted to rotate aroundthe longitudinal axis of the latter.

This ability of the outlet slot 20 to be sealed off is also advantageousif the operation of the device is interrupted or the filling member 15is to be raised to release the cover strip 3 which is filled with filterelements 1 and 2 and located thereunder, after the clamping screws 27have been released. The upper part 35 of the guide rail 25 is sodesigned in the terminal area 34 of slide member 19 that the cover strip3 is given the shape of a closed tube, a suction device 36 beingprovided to suck off any fluent filter material which may possibly belocated between the edges of the cover strip.

A closure device 37 is provided to connect the edges of the cover stripwhich are now overlapping each tween the outside of the filter elementsand the inside of the cover strip and thence into the mouth of thesmoker when the filters are attached to the cigarettes, which occurrenceis very troublesome, it is important that the cover strip is glued tothe filter elements over the whole of their periphery.

To this end the heatable element 38 is provided with a guide channel 39which is semicircular in shape when seen in cross-section, and whoseradius of curvature corresponds to the external radius of the tube whichis to be produced. In order to achieve an exact diameter of the tubewhich is to be produced a further analogous guide channel 40 of acooling member 41 which is adapted to be placed on to the tube is houseddirectly behind the guide channel 39 of the heatable element 38, inorder to set the heat-softened plastics material (FIG. 7).

After the tube has been glued it is led to a separating device 42 inwhich it is subdivided in such a way that the length of each filterstructure amounts to six times the length of one cigarette filter.

A further glueing device 43 is provided (FIGS. 1 and 8) behind theseparating device 42, and its heating element 44 lies against the tubefrom below. The guide channel 45 of this heating element has asemicircularshaped cross-section and connects the part of the coverstrip 3 which has been shaped to form a tube which is not yet glued tofilter elements 1 and 5, with the result that the latter are completelyglued to the cover strip 3 over the whole of their periphery and nofluent filter material can escape from the chambers 17, between thefilter element surfaces and the cover strip 3. Endless, coiled rotatingwires 46 exert pressure on the upper side of the tube sections.

The chambers of the filters are completely filled in this device, andthe complete liberation of the filter element surfaces from fluentfilter material and dust from filter materila by the stripping member 31and the suction device 36 results in a clean cutting surface when thefilter elements are separated by the separating device 51. By glueingthe filter elements over their whole periphery to the cover strip thereis an additional guarantee that no fluid filter material can pass intothe smokers mouth.

What we claim is:

l. The method for making a triple filter unit for subsequent attachmentto the end of a tobacco-filled cigarette and wherein said filter unit isconstituted by two cylindrical filter elements of a fibrous materialseparated by a cylindrical filter element composed of granular filtermaterial, which comprises the steps of;

arranging a series of said fibrous filter elements in longitudinalspaced relation along a longitudinally traveling cover stripintermediate the side edges thereof, said cover strip having a widthwhich exceeds the circumference of the filter elements and beingprovided with a heat-softenable adhesive surface engageable with thesurface of the filter elements,

heating said traveling cover strip so as to effect softening of theadhesive surface thereof,

wrapping said heated cover strip longitudinally to form an upstandingsubstantially U-shaped enclosure which surrounds and becomes adhered tothe lower surface portions of said longitudinally spaced filterelements,

passing said U-shaped cover strip with the lower surface portions ofsaid filter elements adhered thereto through a filling station whereingranular filter material is discharged from a source of supply throughthe top opening provided by the upstanding portions of said U-shapedenclosure into the spaces existing between the ends of consecutivefilter elements,

thereafter wrapping the upstanding portions of said U-shaped cover striparound the remaining surface portions of said filter elements to form anoverlapped joint which thereby completes a full enclosure of the filterelements by said cover strip, and

heating said wrapped around cover strip thereby to effect adhesionbetween the overlapped portions of said cover strip as well as betweensaid cover strip and all other remaining non-adhering surface portionsof said filter elements.

2. The method as defined in claim 1 wherein the heating of said wrappedaround cover strip is effected in two steps separated by a cooling step,the first of such heating steps serving to effect adhesion between theoverlapped portions of said cover strip as well as adhesion between theupper half of said cover strip and the corresponding upper surfaceportions of said filter elements, said cooling step serving to set theadhesive and establish the final diameter of said cover strip, and saidsecond heating step serving to effect adhesion between the lower half ofsaid cover strip and the corresponding remaining non-adhering lowersurface portions of said filter elements.

3. Apparatus for making a triple filter unit for subsequent attachmentto the end of a tobacco-filled cigarette and wherein said filter unit isconstituted by two cylindrical filter elements of a fibrous materialseparated by a cylindrical filter element composed of granular materialwhich comprises;

means for arranging a series of said fibrous filter elements inlongitudinal spaced relation along a longitudinally traveling coverstrip intermediate the side edges thereof, said cover strip having awidth which exceeds the circumference of the filter elements and beingprovided with a heat-softenable adhesive surface engageable with thesurface of the filter elements,

means for heating the central portion of said traveling cover strip soas to effect softening of the adhesive surface thereof,

means for wrapping said heated cover strip longitudinally to form anupstanding substantially U-shaped enclosure which surrounds and becomesadhered to the lower surface portions of said longitudinally spacedfilter elements,

a filling station through which said U-shaped enclosure is passed andwherein granular material is discharged from a source of supply throughthe top opening provided by the upstanding portions of said U-shapedenclosure into the spaces existing between the ends of consecutivefiltered elements,

first guide means through which said U-shaped enclosure is passed afterleaving said filling station and wherein the upstanding portions of saidenclosure second guide means through which said tube is passed afterleaving said first guide means, said second guide means including asubstantially semicircular cooled surface whose radius of curvaturecorresponds to the desired outside radius of the tube and which contactsthe surface portions thereof heated by said first guide means tosolidify the heat-softened adhesive, and

third guide means through which said tube is passed after leaving saidsecond guide means, said third guide means including a substantiallysemi-circular adhesive softening heating surface contacing the lowerhalf of said tube and which serves to adhere the remaining non-joinedsurface portions thereof to the corresponding surface portions of saidfilter elements.

4. Apparatus as defined in claim 3 for making a triple filter unit forcigarettes wherein said means for heating the central portion of saidtraveling cover strip includes a heating element mounted for movementtowards and away from the side of the cover strip remote from thefibrous filter elements, and an adjustment mechanism for bringing saidheating element close to the cover strip when the latter is traveling soas to soften the adhesive surface in contact with the filter elements,and for moving said heating element away from said cover strip when thelatter is stationary thereby to prevent damage to said cover strip bythe heat radiated from said heating element.

1. The method for making a triple filter unit for subsequent attachmentto the end of a tobacco-filled cigarette and wherein said filter unit isconstituted by two cylindrical filter elements of a fibrous materialseparated by a cylindrical filter element composed of granular filtermaterial, which comprises the steps of; arranging a series of saidfibrous filter elements in longitudinal spaced relation along alongitudinally traveling cover strip intermediate the side edgesthereof, said cover strip having a width which exceeds the circumferenceof the filter elements and being provided with a heat-softenableadhesive surface engageable with the surface of the filter elements,heating said traveling cover strip so as to effect softening of theadhesive surface thereof, wrapping said heated cover striplongitudinally to form an upstanding substantially U-shaped enclosurewhich surrounds and becomes adhered to the lower surface portions ofsaid longitudinally spaced filter elements, passing said U-shaped coverstrip with the lower surface portions of said filter elements adheredthereto through a filling station wherein granular filter material isdischarged from a source of supply through the top opening provided bythe upstanding portions of said U-shaped enclosure into the spacesexisting between the ends of consecutive filter elements, thereafterwrapping the upstanding portions of said U-shaped cover strip around theremaining surface portions of said filter elements to form an overlappedjoint which thereby completes a full enclosure of the filter elements bysaid cover strip, and heating said wrapped around cover strip thereby toeffect adhesion between the overlapped portions of said cover strip aswell as between said cover strip and all other remaining nonadheringsurface portions of said filter elements.
 2. The method as defined inclaim 1 wherein the heating of said wrapped around cover strip iseffected in two steps separated by a cooling step, the first of suchheating steps serving to effect adhesion between the overlapped portionsof said cover strip as well as adhesion between the upper half of saidcover strip and the corresponding upper surface portions of said filterelements, said cooling step serving to set the adhesive and establishthe final diameter of said cover strip, and said second heating stepserving to effect adhesion between the lower half of said cover stripand the corresponding remaining non-adhering lower surface portions ofsaid filter elements.
 3. Apparatus for making a triple filter unit forsubsequent attachment to the end of a tobacco-filled cigarette andwherein said filter unit is constituted by two cylindrical filterelements of a fibrous material separated by a cylindrical filter elementcomposed of granular material which comprises; meaNs for arranging aseries of said fibrous filter elements in longitudinal spaced relationalong a longitudinally traveling cover strip intermediate the side edgesthereof, said cover strip having a width which exceeds the circumferenceof the filter elements and being provided with a heat-softenableadhesive surface engageable with the surface of the filter elements,means for heating the central portion of said traveling cover strip soas to effect softening of the adhesive surface thereof, means forwrapping said heated cover strip longitudinally to form an upstandingsubstantially U-shaped enclosure which surrounds and becomes adhered tothe lower surface portions of said longitudinally spaced filterelements, a filling station through which said U-shaped enclosure ispassed and wherein granular material is discharged from a source ofsupply through the top opening provided by the upstanding portions ofsaid U-shaped enclosure into the spaces existing between the ends ofconsecutive filtered elements, first guide means through which saidU-shaped enclosure is passed after leaving said filling station andwherein the upstanding portions of said enclosure are overlapped to forma tube totally enclosing said fibrous filter element and the granularfilled spaces therebetween, said guide means including an adhesivesoftening heating element having a substantially semicircular heatingsurface contacting the overlapped portions of said tube and whose radiusof curvature corresponds to the desired outside radius of the tube, saidheating element serving to adhere the upper surface portions of saidfilter elements to said tube, second guide means through which said tubeis passed after leaving said first guide means, said second guide meansincluding a substantially semicircular cooled surface whose radius ofcurvature corresponds to the desired outside radius of the tube andwhich contacts the surface portions thereof heated by said first guidemeans to solidify the heat-softened adhesive, and third guide meansthrough which said tube is passed after leaving said second guide means,said third guide means including a substantially semi-circular adhesivesoftening heating surface contacing the lower half of said tube andwhich serves to adhere the remaining non-joined surface portions thereofto the corresponding surface portions of said filter elements. 4.Apparatus as defined in claim 3 for making a triple filter unit forcigarettes wherein said means for heating the central portion of saidtraveling cover strip includes a heating element mounted for movementtowards and away from the side of the cover strip remote from thefibrous filter elements, and an adjustment mechanism for bringing saidheating element close to the cover strip when the latter is traveling soas to soften the adhesive surface in contact with the filter elements,and for moving said heating element away from said cover strip when thelatter is stationary thereby to prevent damage to said cover strip bythe heat radiated from said heating element.